PDA

View Full Version : Fuel petcocks


pjslawncare/landscap
01-15-2004, 08:44 PM
The engine manufacturers recomend that you turn off your fuel petcocks overnite. Do you? Has anyone damaged your engine by not following this rule? tell us about it

lawnman_scott
01-15-2004, 08:51 PM
What is a fuel petcock? Shutoff switch? If so, no i dont ever shut it off unless im working on the carburator or something.

burnandreturn
01-15-2004, 08:52 PM
I know someone that had a float stick in the carb. and the gas kept draining down into the cylinder and blew up next time they tried to start up. That was on a Dixon with a B & S engine. They were told they should have shut off the fuel.

battags
01-15-2004, 08:58 PM
That's what I love about this site, you guys are asking the same questions that I am.

Just yesterday, my dealer called to fill me in on one of my mowers he was working on. (Last freebee before the warranty is up). He said that the was changing the oil and it looked a little "thin". He asked if I was shutting off the fuel before transporting it or storing it overnight. I guess the fuel can somehow mix with oil if you transport it with the fuel petcock on? I've only shut the darn valve off when changing the fuel filter....

Anyone ever heard of this?


:confused:

B

pjslawncare/landscap
01-15-2004, 09:00 PM
Originally posted by lawnman_scott
What is a fuel petcock? Shutoff switch? If so, no i dont ever shut it off unless im working on the carburator or something.
Yes, the valve that turns your fuel off.

walker-talker
01-15-2004, 11:16 PM
On occasion I will shut mine off on my powerseeder while in transport, but other than that....no and never had problems.

scottishmaximus
01-15-2004, 11:24 PM
i only shut mine off when working on carbs.

PaulJ
01-16-2004, 12:00 AM
WE had a three wheeler that the cylider fillup with fuel over night and we couldn't even get it to turn over the next day. Thought it had siezed up. We always shut the fuel off on it after that. I usually only shut my mowers off after the last lawn of the day, or if traveling a little farther. Not all the machines even have a fuel shut off. Or at least on that you can reach.

geogunn
01-16-2004, 12:05 AM
Originally posted by lawnman_scott
What is a fuel petcock? Shutoff switch? If so, no i dont ever shut it off unless im working on the carburator or something.

same here.

GEO

Olylawnboy
01-16-2004, 12:07 AM
I have a 36" Bobcat WB and it once started going KAPOW when I pulled the rope. I spoke to the dealer about the problem and the first question he asked was "do you shut of the gas when not in use?". Of coarse I said no. I turn it off now overnight and in transit and guess what, no more kapow. Now I shut off the gas on all gravity feed machines. BTW, they say the gas can seep down into the crankcase and literally blow up the motor, not a pleasant thought.

olderthandirt
01-16-2004, 12:09 AM
Always shut them off at end of the day. Open up the shop door one morning and gas had emptied out of a tiller, if there had been a flame I would of had a chance to use my ins.


Mac

TJLC
01-16-2004, 06:50 AM
I may be over doing it but I shut mine off after each time I use it and then open it up to start for the next job and so on. I do notice that when I pick one of my mowers up from my dealer after a service, the fuel is usually left on.

65hoss
01-16-2004, 09:18 AM
Yes, everything gets the fuel turned off after using. Whether it goes on the trailer or up for the night. I had the fuel run through the carb once and almost lost my 12.5 kawi over it. Its a habit now, just second nature when using the machines.

mtdman
01-16-2004, 09:18 AM
I've never turned it off, unless working on the carb or gas lines. Never had any problem.

naturescape
01-16-2004, 10:42 AM
I had a 14 Kaw (single cylinder) on an older Bunton. I HAD to turn off the fuel on any transportation between jobs, or the mower would be VERY hard to start, sometimes wouldn't at all. Turning off the fuel made all the difference.

Same thing on Honda engines (the 5 H.P. on aerators to be exact).

If the engine doesn't give you a probelm starting tho, I don't think you need to keep the petcock closed.

battags
01-19-2004, 02:06 PM
I don't understand how shutting off the petcock will stop the gas from mixing with the crankcase oil? After all, there is still gas in the carb and everything else forward of the petcock valve, isn't there? Or is it the weight of the gas in the tank forcing raw gas through the engine?

B

65hoss
01-19-2004, 03:04 PM
Originally posted by battags
I don't understand how shutting off the petcock will stop the gas from mixing with the crankcase oil? After all, there is still gas in the carb and everything else forward of the petcock valve, isn't there? Or is it the weight of the gas in the tank forcing raw gas through the engine?

B

On w/b the fuel in gravity feed. By shutting off the fuel it can't keep running into the crankcase. Yes, the little amount in the carb could I guess, but without gravity pulling on the open fuel line it would be very limited.

dishboy
01-19-2004, 03:32 PM
I have had this happen three times in twenty years, its really inconvient to come out in the morning and have to do a oil change as well as pull the carb down to get the dirt out of the needle and seat. I have never damaged a engine as they would not start as they were gas fouled. You would think I would shut off the pettock but I don't or not for long anyway.

Jimbo
01-19-2004, 03:59 PM
65Hoss is almost perfectly correct in his response. However the fuel forward of the shut-off valve will not get into the motor because it is unable to siphon....

To test this theory take a straw and put it in a glass of water. Now stick your thumb over the end of the straw and lift the straw out of the glass. See how the water stays in the straw?? Same thing with the mower.

I bought a decent mower at a great price from a guy who left the petcock on and filled the cylinder with fuel (because the float stuck). Its a good think it didnt start because when I drained the crankcase oil it was like .5W-30 oil.

Jimbo

65hoss
01-19-2004, 04:14 PM
Originally posted by Jimbo
65Hoss is almost perfectly correct in his response. However the fuel forward of the shut-off valve will not get into the motor because it is unable to siphon....

Jimbo

That is what my wife says. Almost perfectly correct. hahahahaha

Jimbo
01-19-2004, 04:27 PM
:p :p :p :p :p ;)